Ham and Cheese Breakfast Casserole

INGREDIENTS

• 18 (1 ounce) slices white bread, cubed
• 8 ounces cooked ham, cubed
• 2 cups shredded Cheddar cheese
• 1 1/2 cups diced Swiss cheese
• 6 eggs
• 3 1/2 cups milk
• 1/2 teaspoon onion powder
• 2 cups crushed cornflakes cereal
• 1/2 cup butter, melted